The present invention relates generally to electrical connectors, and more specifically to a vacuum tight electrical feedthru where electrical leads pass through the walls of a container in which a high vacuum must be maintained.
A variety of electrical and optical systems are designed to use vessels that maintain a pressure differential between the inside and the outside of the vessel. These systems include lasers and charge coupled device (CCD) arrays which are vacuum cavities as well as systems with pressurized containers.
It is a generally recognized problem in the art that vessels subjected to such significant pressure differentials often need elecctrical feedthru connections between the inside and the outside. Such feedthru connections can cause leaks and hazards in the operation of such vessels.
The task of providing an electrical feedthru for pressurized and vacuum tight vessels is alleviated, to some extent, by the systems presented in the following U.S. Patents, the disclosures of which are incorporated herein by reference:
U.S. Pat. No. 2,932,810 issued to Novak; PA1 p U.S. Pat. No. 3,267,314 issued to Williams et al, PA1 U.S. Pat. No. 4,125,310 issued to Reardon, II. PA1 U.S. Pat. No. 4,398,780 issued to Novotny et al, PA1 U.S. Pat. No. 4,453,795 issued to Moulin, PA1 U.S. Pat. No. 4,526,432 issued to Cronin et al, and PA1 U.S. Pat. No. 4,560,232 issued to O'Hara.
Reardon, II shows a basic fold dot connector. Two wafers are pressed together between pressure plates with contact made only by metallic dots or buttons on one of the wafers. The plastic memory of the dots is used as a spring, which is correlated with the force applied by the opposing plates. A similar metallic button connector is disclosed in the Moulin patent.
Cronin et al show an electrical connector including a flat cable which terminates in an end portion configured to fit within the recess of a cylinder. Mounted on the lower surface of the end portion are a plurality of spaced-apart conductor pads. The upper surface of the end portion interfaces with a resilient compression member. The location of pads are complementary to that of conductor pads on bushing.
Novak shows an electrical connector with printed circuit elements. Novotny et al are concerned with a shielded multiconductor cable connector. O'Hara is included for its showing of an electrical feedthru to a high pressure vessel.
Williams et al disclose an electron tube having a hermetic envelope with terminal rings separated by short ceramic cylinders. In this patent, a metal disk is brazed in a cylinder which, in turn, is brazed to another disk. The ceramic cylinders or rings are metalized and brazed to the adjacent metal parts.
While the above-cited references are instructive, a number of prior art techniques have inherent disadvantages. For example, glass feedthru systems are brittle, temperature sensitive, and act as permanent connections. Note that the term "permanent connection" is not meant to be a complementary expression. The word "permanent" is used in the context that the connection is not demountable or changeable.
Glass sealed pin connectors are heat and shock sensitive, and are also permanent connections. Soldered cable connector interfaces are labor intensive permanent connections that are potentially dirty as the flux used remains to contaminate adjacent areas. Similarly, welded wires are labor intensive and permanent connections.
In view of the foregoing discussion, it is apparent that there currently remains the need for a hermetic, vacuum and pressure tight feedthru system. The present invention is intended to satisfy that need.